algebra
posted by ally on .
Four marbles are drawn at random from a bag containing 7 black marbles and 10 red marbles. Determine the number of outcomes in the sample space of this experiment if the marbles are drawn without replacement.

All black  1
3black, 1red = 4!/(3!1!) = 4
2black, 2red = 4!(2!2!) = 6
1 black, 3red = 4
all red = 1
BBBB
BBBR
BBRB
BRBB
RBBB
BBRR
RRBB
BRBR
RBRB
BRRB
RBBR
RRRB
RRBR
RBRR
BRRR
RRRR